Development of a Data-driven Magnetohydrodynamic Simulation Model for Flux-Emerging Active Regions Leading to Coronal Mass Ejections

日冕物质抛射（CME）是近地空间极端空间天气的主要驱动因素，因此是我们现代技术依赖型社会严重关注的问题。 开发能够模拟CME产生和通过行星际空间传播的先进模型是我们预测CME到达地球的时间及其地球效应的重要一步。 不同复杂性和准确性的CME生成模型已经开发了几十年，从超压等离子体模型，如blob模型，到基于通量绳的模型，有或没有喷发前能量积累的必要性。 在几乎所有的情况下，他们有模型参数，需要调整从一个事件到另一个。 这个为期3年的项目旨在开发一个自洽的，数据驱动的磁流体动力学（MHD）模拟模型CME从低色球层延伸到1 Au，是完全基于第一性原理与最小的设置工作和免费的模型参数。 这项为期三年的研究调查也有望提高公众对空间天气的认识。 作为该项目的一部分，该小组将开发一个网站，该网站将对日冕物质抛射及其在空间气象中的作用进行自我解释，包括将定期发布的基于原始项目结果的图像。 因此，它将为公众提供一个宝贵的教育工具。 项目小组将对数据集进行存档，并应要求与感兴趣的各方分享，如不同的空间物理学和天体物理学小组。 因此，他们的新模型将有助于空间天气预报建模工作，作为整个太阳日光层社区的宝贵科学工具。 该项目的PI是亨茨维尔亚拉巴马大学（UAH）太阳物理学REU项目的项目协调员。 UAH的空间科学系和空间等离子体和空气动力学研究中心（CSPAR）也正在进行其他暑期实习项目。 在这些计划的框架内，项目团队将为UAH的本科生提供引人注目的研究项目，优先考虑来自代表性不足的少数民族的学生。 该项目的研究和EPO议程支持AGS部门在发现、学习、多样性和跨学科研究方面的战略目标。这个为期3年的项目旨在为从低色球层延伸到1 Au的CME开发一个新的数据驱动的MHD模拟模型，该模型完全基于第一原理，设置工作量最少，模型参数免费。 这个新的模型将通过物理上一致的特征边界条件公式由光球上的矢量磁图（由SDO的HMI拍摄）驱动，将跟踪活动区域（AR）的演变，主要是通过通量涌现进入AR的自由能和磁螺旋度的积累。 该项目小组的主要目标是获得极性反转线附近的通量绳的形成，以及最终由环面不稳定性引起的爆发。 然后，研究人员将跟踪CME通过日冕和内日光层的传播，最高可达1 Au，并在每个阶段用各种航天器数据验证他们的结果。 他们已经在我们的多尺度流体动力学模拟套件（MS-FLUKSS）代码中分别开发了由低色球层、过渡区和低日冕组成的局部模拟模型和覆盖全球日冕和内日球层的全球模拟模型。 该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Coronal mass ejections (CMEs) are major drivers of extreme space weather in the near-Earth space, hence a matter of serious concern for our modern, technologically-dependent society. The development of advanced models that could simulate the CME generation and propagation through interplanetary space is an important step toward our capability to predict the arrival times of CMEs at the Earth and their geo-effectiveness. CME generation models of varying complexity and accuracy have been developed for a number of decades now, ranging from over-pressured plasmoid models, such as the blob model, through to flux rope-based models with or without the necessity of energy build-up before the eruption. In almost all the cases, they have model parameters that need to be adjusted from one event to another. This 3-year project aims to develop a self-consistent, data-driven magnetohydrodynamics (MHD) simulation model for CMEs extending from lower chromosphere to 1 AU that is entirely based on first principles with minimum setup effort and free model parameters. This 3-year research investigation is also expected to increase the public awareness about space weather. As part of the project, the team will develop a website, which will be self-explanatory about CMEs and their role in space weather, including images based on the original project’s results that will be regularly posted. As such, it will provide a valuable educational tool to the general public. The project team will archive their data sets and share them with interested parties, such as different space physics and astrophysics groups on request. Hence, their new model will contribute to the space weather forecasting modeling efforts as a valuable scientific tool for the solar-heliospheric community at large. The PI of the project is the Program Coordinator of the Heliophysics REU program at the University of Alabama in Huntsville (UAH). There are also other summer internship programs ongoing at the UAH’s Department of Space Science and Center for Space Plasma and Aeronomic Research (CSPAR). Within the framework of these programs, the project team will offer compelling research projects to undergraduate students at the UAH, giving preference to students from underrepresented minorities. The research and EPO agenda of this project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research.This 3-year project aims to develop a new data-driven MHD simulation model for CMEs extending from lower chromosphere to 1 AU that is entirely based on first principles with minimum setup effort and free model parameters. This new model, which will be driven by vector magnetograms on the photosphere (taken by SDO’s HMI) through a physically-consistent characteristic boundary condition formulation, will track the evolution of active regions (ARs), mainly the build-up of free energy and magnetic helicity into the ARs through flux emergences. The main goal of the project team is to obtain the formation of flux ropes near polarity inversion lines and eventually their eruptions resulting from the torus instability. The investigators will then follow the CME propagation through the corona and inner heliosphere up to 1 AU and validate their results with various spacecraft data at every stage. They have already developed separately their local simulation model consisting of lower chromosphere, transition region, and lower corona and global simulation model covering global corona and inner heliosphere within our Multi-Scale Fluid-Kinetic Simulation Suite (MS-FLUKSS) code. During this project, the team will couple the local and global components of their simulation model.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.